Indoor occupancy ground truth dataset with variable ventilation

Indoor occupancy ground truth dataset with variable ventilation. Overview This dataset contains measurements from a controlled laboratory experiment studying indoor air quality (IAQ) and occupancy detection in a simulated Finnish office environment. The dataset contains several IAQ sensors, and the ventilation rate is also measured. Ventilation rate varies in the dataset. The data was collected to test ventilation control based on occupant count estimates from an ML model. Experimental Setup Test Environment Location: Laboratory designed to simulate a typical Finnish office room Capacity: Up to 4 occupants Dimensions: 2.69m (height) × 2.71m (width) × 3.0m (length) Ventilation System Type: Variable Air Volume (VAV) system Control: Modulated airflow rates via Air Handling Unit (AHU) Configuration: Supply and exhaust setpoint flows maintained at equal rates Temperature control: Temperature maintained by chiller Sensors and Measurements Sensor Measurement Accuracy Miran DLS IAQ.THB-H9+CO2 CO₂ (ppm) ±30 ppm Pressure (mbar) ±1.0 mbar Temperature (°C) ±0.3°C Relative Humidity (%) ±2.5% HDK - Duct CO₂ transmitter / controller CO₂ (ppm) ±40 ppm +3 % Lindab FTCU Airflow (l/s) ±5% Steinel HPD2 Occupant count ** Miran DLS IAQ.THB-H9+CO2 placed inside the room**: 1.75 meters ** HDK - Duct CO₂ transmitter / controller: Measures supply and exhaust air CO₂ inside the duct. Occupancy ground truth: Camera-based computer vision occupant counting sensors, and later manually recorded. Dataset Details The training data includes multiple ventilation control strategies, and in the test data, we controlled ventilation according to occupant count. Occupancy-based control: Base ventilation: 3 l/s (unoccupied) Per-person increment: 6 l/s per detected occupant Update frequency: Every 5 minutes Training Data Note that the test room was renovated after March 2025, including the addition of thermal insulation to the walls. Training data 1: February 2024 - March 2025 Duration: 5 days, 21 hours The collection saw various usage, meaning that the data may be noisier than the training data 2. Sensors: Miran DLS IAQ.THB-H9+CO2, 2x Lindab FTCU, Steinel HPD2 Occupancy data: Camera-based occupancy ground truth Training data 2: October 2025 - November 2025 Duration: 2 days, 20 hours days Sensors: Miran DLS IAQ.THB-H9+CO2, 2x Lindab FTCU, 2x HDK - Duct CO₂ transmitter / controller Occupancy data: Manually recorded occupancy ground truth Ventilation test Period 2: October 2025 - November 2025 Duration: 24 hours Collection method: Manually recorded occupancy ground truth Testing Data Ventilation control testing: 23 hours, 50 minutes Funding This research was funded by the Promotion Centre for Electrical Engineering and Energy Efficiency (STEK ry) grant KITSI2.0.